Not Applicable.
Not Applicable
Not Applicable
1. Field of the Invention
This invention relates to the field of musical instruments. More specifically, the invention comprises a muter capable of diminishing the sound emitted by a piano.
2. Description of the Related Art
FIG. 1 illustrates a piano 10. It fundamentally consists of keyboard assembly 20, frame 12, and lid 14. Those skilled in the art will know that keyboard assembly 20 contains keys, along with attached hammer mechanisms configured to strike the strings when the user strikes a particular key. A large number of strings extend away from keyboard assembly 20 in a generally perpendicular direction, with the strings lying approximately in a single plane. The far end of each string is anchored, directly or indirectly, to frame 12.
All pianos are, of course, designed to produce tones covering a large bandwidth. This fact requires the use of strings having different lengths. Thus, the treble section of the keyboard (to the right in the view as shown) employs strings of shorter length than the mid section. This fact explains the curved shape of frame 12. The structure of a concert piano is therefore quite complex, in that it must encompass several curves.
Those skilled in the art will also know that pianos include a soundboard to amplify the sound produced by each vibrating string. This soundboard is typically a large flat panel, suspended beneath the strings. It is suspended in such a fashion as to minimize damping of any vibration induced by the moving strings. The soundboard is largely responsible for the rich tonal texture produced in a well-made piano. It substantially augments resonance. It also produces certain harmonic frequencies, owing to the tendency of the unified sound board to flex according to its own natural frequencies. Finally, the soundboard also tends to provide enhanced blending of different frequencies to produce beat frequencies.
If the operator strikes a first key in the bass range and a second key in the treble range, these two string sets are located remotely from each other (30 to 40 inches apart, typically). Although the human ear may perceive a beat frequency, the two strings are generally too far apart to produce sympathetic vibrations in each other. Because both sets are close to the soundboard, however, the soundboard can transmit the two frequencies and produce the desired sympathetic vibrations.
Lid 14 is hinged to frame 12. It is contoured to cover the open top of frame 12. The strings lie beneath lid 14 with the soundboard, in turn, lying beneath the strings. The hinge is typically placed on the left side of frame 12 in the view as shown. With lid 14 closed, some of the sound produced by piano 10 is trapped within. In a concert setting lid 14 would be propped open, in order to project sound out toward the audience. Thus, the reader will appreciate that lid 14 does provide some selective muffling of piano 10.
FIG. 2 shows a view of piano 10 from underneath. Piano strings are typically made of steel. They cumulatively place several thousand pounds of compression on frame 12. It is therefore necessary to strengthen frame 12. Anchor structure 22 is attached to keyboard assembly 20. A series of beams 24 extend radially forward from anchor structure 22, terminating in intersections with frame 12. End plate 28 stiffens the leading portion of frame 12, and serves to anchor one of the three legs 16. Numerous other structures, such as pedal assembly 18, are present. These other structures are unimportant to the present invention.
Soundboard 26 lies above beams 24. It is important to realize that there is a significant gap between the tops of beams 24 and soundboard 26. Again, soundboard 26 must be free to oscillate undamped.
Looking at FIG. 2, those skilled in the art will realize that soundboard 26 projects sound downward as well as upward. The closing of lid 14 does nothing to attenuate this downward transmission.
The present invention comprises a muter configured to be placed beneath the soundboard of a piano (in the case of a grand piano) in order to attenuate the downward transmission of sound. The muter employs blocks of acoustic foam, shaped to frictionally engage the structural elements of the piano in order to retain the muter within the piano. The muter is easily installed and removed. A version configured for use with an upright piano is also disclosed.